National has admitted it may have told the mining industry it intended pursuing mining as an economic development policy two years before the 2008 election.

Prime Minister John Key this week said National did not campaign on its plans to look at mineral wealth locked up in the conservation estate at the last election because it didn't have enough information at the time to make the call.

However, Minerals Association chief executive Doug Gordon says the industry's representations to National - based on the data which underpins the Schedule Four Stocktake released last week - received an encouraging response as early as 2006.

"That could well have been the case," Energy and Resources Minister Gerry Brownlee said yesterday.

Mr Gordon said the extent and location of potential mineral wealth had been quite well known for some years. His organisation had made significant efforts to promote the economic benefits of mining to the Government from the late 90s onwards.

National and mining spokesman at the time, Chris Auchinvole - now MP for West Coast-Tasman - proved more receptive in 2006.

"By the time National got a head of steam up it was an easy thing for them to begin to say they were going to start looking for contributions to the ways in which living standards of New Zealanders could be improved.

"They showed an interest in looking at the possible contribution that minerals might make to a much larger effort than we're seeing them make."

Mr Brownlee said National "probably" held discussions with miners before the election. "I think I met with Solid Energy before the election, I don't recall entirely, but I definitely became more interested after the election."

Asked whether he was aware that the mining industry had gained the impression from 2006 that a National Government would look favourably on mining, Mr Brownlee replied he wasn't the spokesman at the time, "so that could well have been the case".

In Parliament this week Opposition leader Phil Goff challenged Mr Key over National's Stocktake announcement, "when discussions had taken place with mining lobby groups before the election?"

Mr Key replied: "There are always ongoing discussions with all sorts of sectors and areas over a long period of time".

Mr Brownlee and Mr Gordon both said they were unaware of any campaign contributions to National from mining companies before the 2008 election. A spokesman for Newmont, which operates the Martha and Favona mines near Waihi, said his company did not make campaign contributions to any political parties in New Zealand.